The braided cords in which a plurality of threads are interlaced with one another are provided with an unique design and flexibility, so that they are applied for various articles, among which a shoe lace is representatively exemplified. Functionally speaking, such shoe lace must be easy to be tied up and hard to be loosened besides its design, in which there have been a lot of proposals in response to the demand for its functionality of being hard to be loosened improving especially in terms of a pair of athletic shoes and as such.
In Document 1, such a technique is disclosed as hooks being provided on one side of a strip of material and loops being provided on the other side thereof so as to bring about fastening effect with which the knots become hard to be loosened, in which it is for sure that the knots once tied up together through the engagement of the hooks and loops turn out to be hard to be loosened whereas the problem lies in that the hooks and loops are entangled with one another when such strip of material is tied up for fastening.
On the other hand, in Document 2, such an elastic cord or lace body is disclosed as comprising an elastic core and a sheath; the portions where the constricting force of the sheath is strong and those where such force is weak are repeated; the diameter of the lace body hardly changes at the portions where such force is strong due to their limited stretchability, but such diameter enlarges at the portions where such force is weak due to the elastic core being contracted so as for the sheath to be slackened and the diameter of the lace body reduces when the elastic core is stretched.
In the state where any pulling force is not applied to the elastic cord disclosed in Document 2 or such cord is free from any force, the apparent diameter of such cord becomes large, but the braided lace comprising the sheath is too soft in its inflated state for such cord to function as a hitching cord to be stuck with the eyelets.
Further, in order to make the hitching effect enhanced, in Document 3 by way of one example, such a fastening cord is disclosed as being braided with a rubber material and a non-stretching material with the knotted center string forming a core, in which the firm protuberances of the center string bring the effect of preventing the cord from slipping at the eyelets, but the problem lies in that the cord becomes hard to get through the eyelets owing to the fact that the presence of such protuberances make the diameter of the cord hardly change even when the cord might be stretched.